Space Worlder

Monday, January 24, 2011

European scientists are being asked whether they still want to go ahead with a pioneering space laser mission.

The Earthcare satellite would study the role clouds and atmospheric particles play in a changing climate.

But difficulties in developing the spacecraft's lidar instrument mean the cost of the venture will likely rise from 450m to 590m euros (£500m).

A review is therefore taking place to assess the science value and technical risks of proceeding.

"European Space Agency (Esa) member states have asked us to bring together all the pros and cons in this formal review," said Dr Volker Liebig, Esa's director of Earth observation.

"They want us to speak to the scientists, to look into whether there are any alternatives which lead to the same scientific results. We will then take the conclusions of this review to the member states so they can decide what to do," he told BBC News.

Earthcare was chosen to be one of Esa's Earth Explorers - a series of spacecraft that will do innovative science in obtaining data on issues of pressing environmental concern.

Three missions have so far gone into orbit, returning remarkable new information on gravity, polar ice cover, soil moisture and ocean salinity.

Earthcare is in line to be the sixth Explorer. It would study how clouds and aerosols (fine particles) form, evolve and affect our climate, the weather and air quality.

Different sorts of cloud have different effects. For example, low cloud can help cool the planet while high cloud can act as a blanket.

Developing the primary instrument on Earthcare to get at this information has proved extremely problematic, however.

The intention is to use a lidar, which would fire pulses of ultraviolet light down into the atmosphere.

From the way this light is scattered back to the spacecraft, scientists would be able to build up a picture of where in the atmosphere different cloud types and aerosols reside, and work out their impact on the energy budget of the Earth.

But the instrument's prime contractor, EADS Astrium SAS (Toulouse), has had a torrid time arriving at a design that would reliably work in the vacuum of space.

In tests, engineers found the instrument would contaminate itself with molecular deposits released from the mechanism's own materials whenever they ran the laser in conditions similar to those expected in orbit.

"It was only happening when we operated it in a vacuum," explained Dr Liebig.

"We've had to organise a lot of research but we now understand what happens. It led to the decision that we should go from a monostatic laser which means you have the transmitting and receiving parts in one, to a bi-static laser which divides the two. On top of that, we pressurise the laser. This is a big change."

The final preferred configuration has delayed Earthcare's progress and added significantly (140m euros) to the projected total mission cost.

It is unlikely now that Earthcare can get into orbit before 2016 - two years later than recent estimates.

Some of the extra cost - about two-thirds - is a result of the additional investment required to build the lidar in the new configuration, but part of the inflation - about one-third - is a consequence of having to use a more powerful rocket to launch what will now be a bigger and heavier satellite.

Earthcare will require the more expensive Soyuz vehicle rather than the less expensive Vega rocket.

Esa's Earth observation programme board has asked for a review of the Earthcare project.

The agency's member states want to establish the technical risks of moving ahead with the mission.

They want to know that costs will not go on climbing; and they also want reassurance that the promised advances in scientific knowledge can still be delivered by the satellite.

Professor Anthony Illingworth from Reading University, UK, is the European chair of the panel of scientists that advises Esa on the Earthcare mission.

He told BBC News that there was still a huge amount of knowledge to be gained from flying a space lidar.

"When we look at climate models, the principal cause of uncertainty is the clouds," he said.

"There is a big, what we call, 'forcing effect' from high and low-levels clouds, and at the moment they almost cancel out - the effect of the clouds on the Earth is a slight cooling. But of course in a future climate, if the balance of high and low-level clouds changes - which is why Earthcare is important because it would tell you where the clouds are - and you get more high-level clouds then that would warm the Earth up even more."

The scientific case has also been bolstered in the past year by the Eyjafjallajokull eruption in Iceland, which led to economic losses across the EU put at many hundreds of millions euros. One of the most valuable datasets in determining the precise distribution of the volcanic plume came from the lidar on the US Calipso satellite. Earthcare could undoubtedly make a similar contribution if such conditions were ever repeated.

Like all Esa missions, the Earth Explorer is a pan-European effort.

Industrially, it is managed by the German section of EADS Astrium (Friedrichshafen), but significant parts of the spacecraft are being fabricated in the UK.

These include the main structure of the satellite at Astrium UK (Stevenage), and two additional instruments, at SSTL (Guildford) and SEA Group Ltd (Frome).

A fourth instrument, a cloud profiling radar, is being supplied by the Japanese Space Agency (Jaxa).

Esa member state delegations will meet to discuss the Earthcare review most likely at the end of March.

Space on Canadian oil pipelines will remain tight through at least the end of February, as Enbridge Inc (ENB.TO) and Kinder Morgan Energy Partners (KMP.N) both said on Monday their lines can't ship as much crude next month as customers have requested.

Enbridge, whose lines carry the bulk of oil shipments to the United States from Canada, the biggest U.S. supplier, said five of its lines in the Lakehead system would be apportioned, or rationed, in February. The system distributes oil to refiners in the U.S. Midwest and on to the storage hub at Cushing, Oklahoma.

Capacity on Canadian oil pipelines has been tight since this summer, when two of Enbridge's lines in the Midwest ruptured, backing up crude supplies in Alberta. Oil producers have since been trying to winnow down Alberta stockpiles, routinely requesting more space than available on the lines leaving the province.

Much of that excess Alberta oil has been making its way to the Cushing hub, where tanks are already brimming with crude. Analysts have tagged the rising volumes of Canadian crude to Cushing as a factor behind a widening spread between U.S. benchmark oil prices and Brent, the world marker.

Enbridge said the February apportionment is result of temporary capacity restrictions one some of its lines as it steps up inspections following the two ruptures, as well as high nominations from shippers.

It said lines 6A, 14 and 62, which carry Canadian oil from Superior, Wisconsin, to Illinois, Indiana and on to Cushing are apportioned at 7 percent, so that shippers will get only 93 percent of the space they have requested.

Line 6B, which was closed for nine weeks last year after a rupture spilled more than 20,000 barrels into a Michigan river system, is apportioned at 16 percent.

Enbridge's 490,000 barrel per day Line 5, which runs from Superior to Sarnia in southern Ontario, is apportioned by 23 percent as the company steps ups maintenance and inspection work.

TRANS MOUNTAIN RATIONING

Kinder Morgan is again rationing capacity on its Trans Mountain pipeline system, which takes Alberta crude to southern British Columbia and Washington's Puget Sound, as shippers wanted to put more oil on the line than it could carry.

Kinder Morgan said on Monday that it cut back shipper nominations for space on the system next month by 33 percent, meaning the system's customers will get to ship only 67 percent of the volumes requested.

The Pune Mahanagar Parivahan Mahamandal Ltd (PMPML), struggling to find enough parking space at bus-stands and terminuses for its fleet of 1,550 buses, has been robbed of a plot of prime land reserved for a bus terminus (in the 1987 development plan). Through a government resolution (GR) the state government has changed the status of the 21,000 square feet plot in upmarket Deccan Gymkhana into a parking space for citizen's vehicles.

Civic activists alleged that it was an attempt to hand over the plot to a builder to construct a parking space in one part and use the remaining for his own commercial interest. PMPML officials expressed disappointment that plot had been converted despite their protests.

“We need the plot as we are facing a space crunch. We had registered our objection to changing the reservation. Despite it, this has happened. We are completely in the dark about this,” said PMPML joint managing director Satish Kulkarni.

PMPML officials say they had registered objections with the Pune Municipal Corporation and the Deputy Director of Town Planning. officials of the transport body, however are not directly blaming the PMC as being behind the move. “We have no clue who is behind the move. Who and how it was done, we can't say,” officials said.

When contacted, PMC Additional City Engineer Vivek Kharawadkar confirmed that the plot has been converted into a parking space for citizens. “We have received the government resolution. On Monday, I will provide the entire process as to how it came about,” he said.